<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            margin: 0px;
            padding: 0px;
        }

        .main-container {
            display: flex;
        }

        .aside-left {
            width: 200px;
            height: 100vh;
            background-color: #ffff00;
        }

        .aside-right {
            height: 100vh;
            /* 占满所有剩余空间 */
            flex-grow: 1;
            background-color: aqua;
        }

    </style>
</head>
<body>
    <main class="main-container">
        <aside class="aside-left">左侧</aside>
        <section class="aside-right">右侧</section>
    </main>
</body>
</html>